nfsd4: permit layoutget of executable-only files

Clients must be able to read a file in order to execute it, and for pNFS
that means the client needs to be able to perform a LAYOUTGET on the file.

This behavior for executable-only files was added for OPEN in commit
a043226bc1 "nfsd4: permit read opens of executable-only files".

This fixes up xfstests generic/126 on block/scsi layouts.

Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

fs/nfsd/nfs4proc.c

@@ -1363,14 +1363,14 @@ nfsd4_layoutget(struct svc_rqst *rqstp,
 	const struct nfsd4_layout_ops *ops;
 	struct nfs4_layout_stateid *ls;
 	__be32 nfserr;
-	int accmode;
+	int accmode = NFSD_MAY_READ_IF_EXEC;
 
 	switch (lgp->lg_seg.iomode) {
 	case IOMODE_READ:
-		accmode = NFSD_MAY_READ;
+		accmode |= NFSD_MAY_READ;
 		break;
 	case IOMODE_RW:
-		accmode = NFSD_MAY_READ | NFSD_MAY_WRITE;
+		accmode |= NFSD_MAY_READ | NFSD_MAY_WRITE;
 		break;
 	default:
 		dprintk("%s: invalid iomode %d\n",